Bronze SupporterBronze Supporter

Putting together parts for my first build. Going to be 300BO SBR (8.5") Suppressed.

Looking at types and brands of Adjustable Gas blocks to use. Didn't see any recent discussion here about clamp vs drilled install. Why one and not the other? Anyone know of a clamp on adjustable that fits under a rail?

Well-Known Member

Using micro gas blocks, I dimple the barrel by using longer screws that are ground to a point. Be sure to use the appropriate "offset" washer for alignment of the gas port if necessary. Assemble the barrel and gas block in it's final mounted form, and mount to the upper. My method is with charging handle and bolt carrier group in place. Once happy with alignment, turn screws into barrel to "mark" drill points. I then use a piece of brass tubing around a 1/16" drill bit (with a stop collar) to drill the dimple to a depth of 1/8". Then I remove the gas block, and drill the dimple to one size down from the hex screw diameter.

I think that's the one I used on most of my builds. Then the options for rails and such expand
The only type I know that are drilled are the pinned ones.Then the barrel needs to have the bottom relieved for the pins.
Otherwise I can't see any reason to drill anything
Easiest way to see if it's aligned correctly is just spray some cleaner,thru the little red tube,into the gas tube. If the cleaner comes out of the port in the barrel you have the block set correctly

Bronze SupporterBronze Supporter

Syrac adjustable with set screw or clamp on have yet to let me down. A dimple opposite the gas port greatly aids in getting the gas block aligned with that port. A misaligned gas block can act like several other gremlins that will have you tearing your hair out, making you hate your new AR build.

Bronze SupporterBronze Supporter

I've heard some good things on these guys. It may come down to where the adjustment screw is compared to my rail. Visualizing in my mind that the front adjusting may be an issue if I have my rail longer to cover the can....

Bronze SupporterBronze Supporter

Syrac adjustable with set screw or clamp on have yet to let me down. A dimple opposite the gas port greatly aids in getting the gas block aligned with that port. A misaligned gas block can act like several other gremlins that will have you tearing your hair out, making you hate your new AR build.

Click to expand...

I see myself having to watch some vids on this process. Likely that parts will come from Curt's so hopefully they will offer assistance when the time comes....

CurmudgeonSilver Supporter2015 Volunteer

I've heard some good things on these guys. It may come down to where the adjustment screw is compared to my rail. Visualizing in my mind that the front adjusting may be an issue if I have my rail longer to cover the can....

Click to expand...

The round, hollow hand guard on the 24" Varminter barrel fits over this gas block, and the block can be adjusted from the front without removing the hand guard.

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